Such a roller shutter profile is known for example from EP 0 225 862 A1 as well as EP 0 732 469 A1. The known roller shutter profiles are used in particular in the form of extruded plastic profiles for swimming pool covers. Since the swimming pool covers lay on the water surface and should swim on the water surface due to the air-filled hollow chambers, it is important that the roller shutter profiles are occluded at their ends. Since such roller shutter profiles are used in the outside, special attention must be given to the fact that both the material of the roller shutter profile per se as well as the material of the closure are weatherproof, i.e. it must be especially resistant to UV radiation and larger temperature fluctuations. It is not permitted that the materials become brittle during the service life of such covers or will warp as a result of temperature fluctuations, which would lead to leakages.
In the roller shutter profiles as are known from EP 0 225 862 A1 as well as EP 0 732 469 A1 the piston plates are each connected via a piston-rod-like shaft with the cap. The cap comprises a stopper section which is adjusted to the cross section of the respective hollow chamber and is introduced into the same. The cross section of the piston plate is similarly adjusted to the cross section of the hollow chamber. The impermeability is produced in such a way that the intermediate space between the piston plate and the stopper section is filled at first with sealing medium which is free-flowing at first, which sealing medium is introduced through an opening in the stopper section of the cap from the outside by means of a suitable filling means. The sealing medium which is based on a plastic material shows favorable adhesive properties which produce a permanent connection of the same with the walls of the hollow chamber and cures after a certain period of time. In this way a permanent closure of the roller shutter profile can be achieved which cannot be reversed. Whereas each hollow chamber is associated with its own supply opening and a venting or overflow opening adjacent thereto in the roller shutter profiles as known from EP 0 225 862 A1, the further development as known from EP 0 732 469 A1 is that adjacent hollow chambers can be closed off by way of a single filling process. For this purpose the liquid scaling medium flows at first through a supply opening into the first hollow chamber in order to then pass through an overflow duct into the adjacent hollow chamber and to move from there to further adjacent hollow chambers, if any. In the last hollow chambers which are thus connected in series there is a venting or overflow opening in the associated stopper section of the cap, so that the filling process can be ended at the time when the sealing medium emerges from said opening.
Even though it was possible to achieve a reduction of the working time in the production of waterproof closures in the further development as described in EP 0 732 469 B1, the use of such free-flowing and curing sealing mediums is generally problematic. One disadvantage is that the closures cannot be mechanically loaded directly after the filling with the sealing medium because it reaches the required hardness only after a certain period of time, i.e. it is capable of withstanding the action of a force. Moreover, the filling of the sealing medium into the intermediate space between the piston plate and the sealing cap can only occur with a certain conveyance rate, so that in practice there is a required time per hollow chamber to be filled of several seconds. A further disadvantage is that interruptions in the filling process lead to a curing of the sealing medium also in the filling apparatus, so that time-consuming cleaning work is necessary prior to resuming the filling.